I was reading my son a story last night. A great tale of derring-do of five mountaineers scaling the Matterhorn for the first time. One in the party had tried six times previously and failed, this was the last attempt before winter closed another season.
They tried a new route, scaling from the north face. The route was climable but there was a particularly treacherous precipice, the climbers roped themselves together and inched sideways along a narrow ledge just centimetres wide. Success. The party made it to the top. They surveyed the land lying before them and saw, just a few hundred metres below, the rival Italian party also vying for the glory of conquering this last unscalable European peak.
But, the fame was to go to the English/French and they began their descent. Once again roped together they inched back across the ledge but this time a climber fell pulling his fellow climber and friend with him. The rope securing them to the rest of the party was cut to save lives but two were lost that day on the mountain. Of the five climbers, only three returned to triumph and accolades.
Earlier in the day, I had been asked to comment as a toxicologist on why glyphosate (Roundup™) hasn’t yet been banned. A recent case in the US where a worker successfully prosecuted the chemical manufacturing company Monsanto has raised concerns around the safety of this chemical and whether it should be used. Hasn’t an international agency said it causes cancer? And what does this have to do with the 1865 ascent of the Matterhorn?
Risk vs Hazard
The link is risk. Most people understand that mountain climbing is risky. If you go mountain climbing and edge along a narrow precipice there is risk involved. Similarly, there is risk involved with using chemicals, some chemicals are even labelled “hazardous” so is using them a risk? Actually, hazard and risk are different, a hazard is something that is dangerous, like a very narrow precipice. But, the hazardous precipice is only a risk if we go near it. Falling from the precipice is clearly a hazard that could kill someone, but you are not at risk of falling unless you are climbing along it.
Determining if something is hazardous is therefore quite different to determining the risks associated with it. Glyphosate has been identified as a hazard by an international agency (IARC) who looked at a lot of data and decided it is a probable human carcinogen (might cause cancer). But this doesn’t tell us about the risk.
When does it cause cancer, how much contact do you need, how often, after how long, is everyone susceptible or only some people, if so who are they? These are really important questions that help us understand the hazard and minimise the risk. Just like we don’t all want to walk every day around roped to a friend so that we don’t fall off a precipice which is actually 18,000 km away on the side of a mountain, we don’t necessarily want to stop using a valuable chemical if it is safe. But, we do need to try and fully understand the risk to humans and the environment so that we can take appropriate action such as wearing protective gear or only using the chemical in certain circumstances.
To fully understand the risks and decide how we use a chemical we need information. First, we need scientific information. The science says that while glyphosate can cause cancer (it is a hazard) it has a very low risk of causing cancer. For comparison, it is in the same hazard category as red meat, coffee and other hot beverages, and working as a hairdresser. But remember, the IARC doesn’t identify risk, only hazard. The IARC classification tells scientists and regulators that these chemicals can cause cancer and that they need to look at the associated risk to they can develop advice on how we can use the chemical safely. We don’t need to stop drinking coffee because it causes cancer but we should all be careful of repeatedly drinking beverages that are extremely hot as it can cause throat damage.
As well as the science we need society to judge what is an acceptable risk and what is not. This is often referred to as the risk:benefit equation. Mountaineers judge that the risk of falling from a precipice and dying is acceptable if they are to claim the glory of being first to climb the Matterhorn. However, I personally do not want to die falling from a precipice and so am not going to go mountain climbing. With medication, we accept the greater risk of side effects (toxicity) from cancer medicines than we do from headache pills because the benefits are vastly different.
It is up to society whether the very low risk of cancer from using glyphosate is acceptable and when. Should it be used by councils? To answer this, we need to know what the alternatives are. Even purportedly “safe” chemicals such as cider vinegar have risks, what are they? How do they compare to glyphosate? What happens on farms, is the assessment different there?
The questions are hard and the solutions are often complicated. But, to have the debate we need to understand risks and hazards and realise they are not the same. We need to think about the exceptions and nuances as it is unlikely that the solution is either a complete ban or unregulated use for everything. So, my answer to should we ban glyphosate is – it depends, how far away from the mountain are you?
Dr Belinda Cridge is a toxicologist at the University of Otago.